5.17 Understand how evolution (a change in the allele frequency) can come about through gene mutation
and natural selection.
Evolution
• Evolution: A change in the frequency of an allele in a population over time.
• Individuals within a population vary because they have different alleles.
• The different alleles are due to gene mutations (changes in the DNA base sequence of genes.
• Individuals that have an allele that increase their chances of survival are more likely to survive and
reproduce to pass on their genes.
• This means that a greater proportion of the next generation inherit the beneficial allele.
• The frequency of the beneficial allele increases from generation to generation.
Geonomics
• Geonomics is a branch of science that uses DNA technology to determine the base sequence of an
organism’s genome and the functions of its genes.
• This allows scientists to make comparisons between organisms’ DNA.
• The theory of evolution suggests that all organisms have evolved from shared common ancestors.
• Closely related species diverged (evolved to become different species) more recently.
• Evolution is caused by gradual changes in the base sequence of organisms’ DNA.
• Organisms that diverged away from each other more recently should have more similar DNA, as less
time has passed for changes in the DNA sequence to occur.
Proteonomics
• Proteonomics is the study of proteins, e.g. the study of the size, shape and amino acid sequence of
proteins.
• The sequence of amino acids in a protein coded for by the DNA sequence in a gene.
• Related organisms have similar DNA sequences and so similar amino acid sequences in their
proteins.
• Organisms that diverged away from each other more recently should have more similar proteins as
less time has passed for changes to occur.
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